MULTIVIR, INC. PROMISSORY NOTE

Exhibit 4.2

THIS NOTE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ACT”), OR UNDER THE SECURITIES LAWS OF CERTAIN STATES. IT MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED EXCEPT AS PERMITTED UNDER THE ACT AND APPLICABLE STATE SECURITIES LAWS PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT OR AN EXEMPTION THEREFROM. THE ISSUER OF THIS NOTE MAY REQUIRE AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE ISSUER THAT SUCH OFFER, SALE OR TRANSFER, PLEDGE OR HYPOTHECATION OTHERWISE COMPLIES WITH THE ACT AND ANY APPLICABLE STATE SECURITIES LAWS.

MULTIVIR, INC.

PROMISSORY NOTE

FOR VALUE RECEIVED, MultiVir, Inc., a Delaware corporation (the “Company”), promises to pay to Pope Investments II LLC (“Lender”), or its registered assigns, in lawful money of the United States of America the principal sum as set forth in the Schedule of Amounts Drawn attached hereto as Schedule I, as may be updated and amended from time to time as the Company draws upon the Credit Facility which governs the issuance of this note, together with simple interest on the actual principal balance outstanding hereunder from time to time at a rate equal to 6% per annum, computed on the basis of the actual number of days elapsed and a year of 365 days. All unpaid principal, together with any then unpaid and accrued interest and other amounts payable hereunder, shall be due and payable on the earlier of (i) December 30, 2016 (the “Maturity Date”), or (ii) when, upon the occurrence and during the continuance of an Event of Default, such amounts are declared due and payable by Lender or made automatically due and payable, in each case, in accordance with the terms hereof.

The following is a statement of the rights of the Lender and the conditions to which this Note is subject, and to which the Lender, by the acceptance of this Note, agrees:

1. Payments.

(a) Interest. Accrued interest on this Note shall be payable at maturity.

(b) Voluntary Prepayment. This Note may be prepaid, in whole or in part, at any time without penalty. Any permitted prepayment of this Note may only be made based on the respective aggregate outstanding principal amounts of the Note, and any such prepayment will be applied first to the payment of expenses due under this Note, second to interest accrued on this Note and third, if the amount of prepayment exceeds the amount of all such expenses and accrued interest, to the payment of principal of this Note. Any partial payment of principal of this Note shall be documented by appropriate amending and updating of the Schedule of Amounts Drawn.

(c) Mandatory Prepayment. The outstanding principal amount of this Note, plus all accrued and unpaid interest, shall be due and payable in the event of a Change of Control, immediately prior to the closing of such Change of Control. For clarity, the amounts due pursuant to this Section 1(c) shall be paid prior to the payment of any amounts (i) under any management retention plan or similar plan of the Company, or (ii) to holders of outstanding equity of the Company in their capacity as such.

2. Events of Default. The occurrence of any of the following shall constitute an “Event of Default” under this Note and the other Transaction Documents:

(a) Failure to Pay. The Company shall fail to pay:

(i) when due any principal payment on the due date hereunder or

(ii) any interest payment or other payment required under the terms of this Note or any other Transaction Document on the date due, and such payment in either case shall not have been made within five (5) Business Days of the Company’s receipt of written notice to the Company of such failure to pay;

(b) Breaches of Covenants. The Company shall fail to observe or perform any other material covenant, obligation, condition or agreement contained in this Note or the other Transaction Documents (other than those specified in Section 2(a)) and such failure shall continue for ten (10) business days after the Company’s receipt of written notice to the Company of such failure;

(c) Representations and Warranties. Any representation, warranty, certificate, or other statement (financial or otherwise) made or furnished by or on behalf of the Company to the Lender in writing in connection with this Note or any of the other Transaction Documents, or as an inducement to the Lender to enter into this Note and the other Transaction Documents, shall be false, incorrect, incomplete or misleading in any material respect when made or furnished;

(d) Voluntary Bankruptcy or Insolvency Proceedings. The Company shall (i) apply for or consent to the appointment of a receiver, trustee, liquidator or custodian of itself or of all or a substantial part of its property, (ii) admit in writing its inability to pay its debts generally as they mature, (iii) make a general assignment for the benefit of its or any of its creditors, (iv) be dissolved or liquidated, (v) commence a voluntary case or other proceeding seeking liquidation, reorganization or other relief with respect to itself or its debts under any bankruptcy, insolvency or other similar law now or hereafter in effect or consent to any such relief or to the appointment of or taking possession of its property by any official in an involuntary case or other proceeding commenced against it, or (vi) take any action for the purpose of effecting any of the foregoing; or

(e) Involuntary Bankruptcy or Insolvency Proceedings. Proceedings for the appointment of a receiver, trustee, liquidator or custodian of the Company, or of all or a substantial part of the property thereof, or an involuntary case or other proceedings seeking liquidation, reorganization or other relief with respect to the Company or any of its Subsidiaries, if any, or the debts thereof under any bankruptcy, insolvency or other similar law now or hereafter in effect shall be commenced and an order for relief entered or such proceeding shall not be dismissed or discharged within 45 days of commencement.

3. Rights of Lender upon Default. Upon the occurrence of any Event of Default (other than an Event of Default described in Sections 2(d) or 2(e)) and at any time thereafter during the continuance of such Event of Default, Lender may, by written notice to the Company, declare all outstanding Obligations payable by the Company hereunder to be immediately due and payable without presentment, demand, protest or any other notice of any kind, all of which are hereby expressly waived, anything contained herein or in the other Transaction Documents to the contrary notwithstanding. Upon the occurrence of any Event of Default described in Sections 2(d) and 2(e), immediately and without notice, all outstanding Obligations payable by the Company hereunder shall automatically become immediately due and payable, without presentment, demand, protest or any other notice of any kind, all of which are hereby expressly waived, anything contained herein or in the other Transaction Documents to the contrary notwithstanding. In addition to the foregoing remedies, upon the occurrence and during the continuance of any Event of Default, Lender may exercise any other right power or remedy granted to it by the Transaction Documents or otherwise permitted to it by law, either by suit in equity or by action at law, or both.

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4. Definitions. As used in this Note, the following capitalized terms have the following meanings:

“Affiliate” shall mean a Person that directly or indirectly, through one or more intermediaries, controls, is controlled by, or is under common control with, the Person specified including, without limitation, any general partner, officer, director or manager of such Person and any venture capital fund now or hereafter existing that is controlled by one or more general partners or managing members of, or is under common investment management with, such Person.

“Change of Control” shall mean (i) any “person” or “group” (within the meaning of Section 13(d) and 14(d) of the Securities Exchange Act of 1934, as amended), becomes the “beneficial owner” (as defined in Rule 13d-3 under the Securities Exchange Act of 1934, as amended), directly or indirectly, of more than 50% of the outstanding voting securities of the Company having the right to vote for the election of members of the Board of Directors, (ii) any reorganization, merger or consolidation of the Company, other than a transaction or series of related transactions in which the holders of the voting securities of the Company outstanding immediately prior to such transaction or series of related transactions retain, immediately after such transaction or series of related transactions, at least a majority of the total voting power represented by the outstanding voting securities of the Company or such other surviving or resulting entity or (iii) a sale, lease or other disposition of all or substantially all of the assets of the Company.

“Credit Facility Agreement” shall mean the Credit Facility Agreement, dated effective as of December 4, 2014 (as amended, modified or supplemented), by and among the Company and the Lender (as defined in the Credit Facility Agreement itself) party thereto.

“Event of Default” has the meaning given in Section 2 hereof.

“Lender” shall mean the Person specified in the introductory paragraph of this Note or any Person who shall at the time be the registered holder of this Note.

“Lien” shall mean, with respect to any property, any security interest, mortgage, pledge, lien, claim, charge or other encumbrance.

“Note” shall mean the promissory note issued pursuant to the Credit Facility Agreement.

“Obligations” shall mean and include all loans, advances, debts, liabilities and obligations, howsoever arising, owed by the Company to Lender of every kind and description, now existing or hereafter arising under or pursuant to the terms of this Note and the other Transaction Documents, including, all interest, fees, charges, expenses, attorneys’ fees and costs and accountants’ fees and costs chargeable to and payable by the Company hereunder and thereunder, in each case, whether direct or indirect, absolute or contingent, due or to become due, and whether or not arising after the commencement of a proceeding under Title 11 of the United States Code (11 U. S. C. Section 101 et seq.), as amended from time to time (including post-petition interest) and whether or not allowed or allowable as a claim in any such proceeding.

“Person” shall mean and include an individual, a partnership, a corporation (including a business trust), a joint stock company, a limited liability company, an unincorporated association, a joint venture or other entity or a governmental authority.

“Securities Act” shall mean the Securities Act of 1933, as amended.

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“Transaction Documents” shall mean this Note, the Warrant and the Credit Facility Agreement.

“Warrant” shall mean the warrant to purchase shares of Common Stock issued pursuant to the Credit Facility Agreement.

5. Miscellaneous.

(a) Successors and Assigns; Transfer of this Note.

(i) Subject to the restrictions on transfer described in this Section 5(a), the rights and obligations of the Company and the Lender shall be binding upon and benefit the successors, assigns, heirs, administrators and transferees of the parties.

(ii) With respect to any offer, sale or other disposition of this Note, the Lender will give written notice to the Company prior thereto, describing briefly the manner thereof, together with a written opinion of Lender’s counsel, or other evidence if reasonably satisfactory to the Company, to the effect that such offer, sale or other distribution may be effected without registration or qualification (under any federal or state law then in effect); provided, however, that no such opinion of counsel shall be required with respect to any offer, sale or other disposition of this Note to an Affiliate of the holder of this Note. Upon receiving such written notice and reasonably satisfactory opinion, if so requested, or other evidence, the Company, as promptly as practicable, shall notify Lender that Lender may sell or otherwise dispose of this Note, all in accordance with the terms of the notice delivered to the Company. If a determination has been made pursuant to this Section 5(a) that the opinion of counsel for Lender, or other evidence, is not reasonably satisfactory to the Company, the Company shall so notify Lender promptly after such determination has been made. Each Note thus transferred shall bear a legend as to the applicable restrictions on transferability in order to ensure compliance with the Securities Act, unless in the opinion of counsel for the Company such legend is not required in order to ensure compliance with the Securities Act. The Company may issue stop transfer instructions to its transfer agent in connection with such restrictions. Subject to the foregoing, transfers of this Note shall be registered upon registration books maintained for such purpose by or on behalf of the Company as provided in the Credit Facility Agreement. Prior to presentation of this Note for registration of transfer, the Company shall treat the registered holder hereof as the owner and holder of this Note for the purpose of receiving all payments of principal and interest hereon and for all other purposes whatsoever, whether or not this Note shall be overdue, and the Company shall not be affected by notice to the contrary.

(iii) Neither this Note nor any of the rights, interests or obligations hereunder may be assigned, by operation of law or otherwise, in whole or in part, by the Company without the prior written consent of the Lender.

(b) Waiver and Amendment. Any provision of this Note may be amended, waived or modified upon the written consent of the Company and the Lender.

(c) Notices. All notices, requests, demands, consents, instructions or other communications required or permitted hereunder shall be in writing and faxed, mailed or delivered to each party at the respective addresses of the parties as set forth in the Credit Facility Agreement, or at such other address or facsimile number as the Company shall have furnished to the Lender in writing. All such notices and communications will be deemed effectively given the earlier of (i) when received, (ii) when delivered personally, (iii) one business day after being delivered by facsimile (with receipt of appropriate confirmation), (iv) one business day after being deposited with an overnight courier service of recognized standing or (v) four days after being deposited in the U.S. mail, first class with postage prepaid..

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(d) Payment. Payment shall be made in lawful tender of the United States.

(e) Usury. In the event any interest is paid on this Note which is deemed to be in excess of the then legal maximum rate, then that portion of the interest payment representing an amount in excess of the then legal maximum rate shall be deemed a payment of principal and applied against the principal of this Note.

(f) Expenses; Waivers. If action is instituted to collect this Note, the Company shall pay all costs and expenses, including, without limitation, reasonable attorneys’ fees and costs, incurred in connection with such action. The Company hereby waives notice of default, presentment or demand for payment, protest or notice of nonpayment or dishonor and all other notices or demands relative to this instrument.

(g) Governing Law. This Note and all actions arising out of or in connection with this Note shall be governed by and construed in accordance with the laws of the State of Delaware, without regard to the conflicts of law provisions of the State of Delaware, or of any other state.

(Signature Page Follows)

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The Company has caused this Note to be issued as of the date first written above.

SCHEDULE I

SCHEDULE OF AMOUNTS DRAWN